My favorite card game of all time is Tarot. It's a deceptively simple game, especially in its basic form—no bidding, no partnerships, none of the mandatory over-trumping that characterizes standard French Tarot (the form of the game most players are familiar with).
A pack of Tarot cards consists of seventy-eight cards: the suit cards (the four common suits: ♥ ♠ ♦ ♣) with fourteen cards in each suit—A (low), 2, 3, 4, 5, 6, 7, 8, 9, 10, Knave, Knight, Queen, King (High) and the twenty-two trump cards or tarots (numbered from 1, low, to 21, high, plus the zero-trump, the Fool).
In basic Tarot, play starts by dealing all of the cards out to all of the (three to five) players. (With 3–4 players, you leave six cards in a widow/kitty/dummy hand; with 5 players, leave three cards out). Play then proceeds as a normal trick-and-trump game, with two wrinkles: if you can follow suit, you must follow suit—you can't even trump unless you've already run out of the suit led; and if you can't follow suit but you can trump, then you must play a trump card, whether it would win the trick or not. (In French Tarot and some other forms, whenever you're compelled to trump, you must also play a higher trump than one already played if able to—"over-trumping". But this rule is absent from the basic game.)
The one exception to these two rules is the Fool card. Throughout most of the game, the Fool (also known as "the excuse") is a card that you can play at any time, regardless of what suits or trumps you still have left in your hand, in order to excuse yourself from playing to that trick. The Fool can't win the trick, but neither does it get taken—when you play the Fool, you keep it and score points for it. This is the case right up until the last trick of the hand, when the Fool ceases to be the excuse and becomes the zero trump—it will win a final trick containing only suit-cards, but if the trick contains any trump cards, highest trump takes the trick, including the Fool.
Tarot is a point-trick game; the objective is to capture tricks with valuable cards. You get 1 point for every trick that you take, plus 1 bonus point for every jack, 2 points for every knight, 3 points for every queen, 4 points for every king, and 4 points for each of the "ends"—the 1 trump, the 21 trump, and the Fool.
And that's all there is to it. It's a simple game, but very strategic and barrels of fun. The hardest part is just finding a good deck to play with. The kinds of Tarot decks that you can get in bookstores are total crap for playing Tarot, for the simple reason that they never have rank and suit indices in the corners of the cards. And when you play three-hand Tarot, you're dealing with a hand of 24 cards per player! Trying to do that with goofy new-age diviner's cards is an exercise in futility.
Thankfully, French gaming Tarots are easily found on ebay. But even then, the cards are large. It's a wonder to me that ordinary poker- (or better yet, bridge-) sized Tarot decks basically don't exist. And so, to remedy that, I decided to seek out some blank playing cards (easily available online; they're used for magic-tricks) and draw my own. Wonder of wonders, on Amazon, I found some blank cards whose backs are standard Bicycle rider-backs! That saved me a great deal of time—I wouldn't need to draw my own spot-cards (I've done it before; very tedious), jacks, queens, or kings—just the knights and the trumps.
The stick-figure design aesthetic is probably a result of my weird sense of humor, my utter lack of artistic talent, and (most especially) my recently having become enamored with Risus: The Anything RPG.
The only real trouble involved in designing these cards was trying to come up with a decent English name for the knight/cavalier. In French decks, the court cards are called Valet, Chevalier, Dame, Roi—Page/Knave, Cavalier/Knight, Lady, King. Traditional German playing cards (regular cards, not Tarot decks) lack the queen altogether, and call the knave and the knight the "Unter" and "Ober" (basically, German decks have an under-jack, an over-jack, and a king).
But English decks stopped calling the knaves knaves long ago, because it was too easy to confuse cards marked "Kn" in the corner with "K" for king. So I wasn't about to call this card-rank "knight", for the very same reason. Neither do I like calling them "cavaliers", because it's a mouthful and it doesn't fit linguistically—it's a long, Latin-derived word, not a nice short Germanic word.
So in the end, I settled on calling them "thanes", a very English word with pretty much the same implication of minor military nobility as "knight". And it sounds good: jack, thane, queen, king. Which is probably a reflection of the Anglo-Saxon roots of each word: jack from Middle English Jan + kin ("John's kin", i.e. anyone, an everyman; the earlier term "knave" is straight-up Old English, cnafa, servant-boy); and the other words from Old English, thegn (replacing cniht), cwen, cyning.
(Holy crap, I just wrote a blog post that combines English linguistics and a 600-year-old card game. Sometimes I worry about me.)